Vitrified paving-brick.



the increasing heat of tion of paving bricks.

- KARL LANG-ENBECK, 035 BOSTON, MASSACHUSETTS.

VITRIFIED PAVING-BRICK.

No Drawing.

To all whom it may concern} Be it known that-I, KARL LANGENBEOK, acitizen of the United States, residing at Boston, in the county ofSufi'olk and State of Massachusetts, have invented certain new anduseful Improvements in Vitrified Pavin'g-Brick, of which the followingis a specification; This invention relates to vitrified pa ing bricks orblocks consisting essentially of a vitrified mixture of sieved coalashes possessing the capability of felting, with a bond of clay which inthe mixture and in presence of the ash is more fusible than the ash.

A preferred composition for making this brick or block consists of fromtwo to three parts by weight of sieved coal ashes commingled with onepart pf blue, boulder or alluvial clay. The proportion of ash may varyconsiderably in accordance with the quality of the ash and the characterof the clay, but shouldbe in all cases suflicient to permit felting ofthe ash component of-the composition. I have found that a mixture ofthis character, on addition of water, yields a body which may becompacted without lamination into a brick or block of remarkabledensity. This is apparently due to the property possessed by sieved coalashes, that is to say the non-fused and refractory por' tion of the ashas distinguished from the more basic and fusible portion known asclinker, in presence of a moderate and not excessive proportion of aclay bond, of felting under pressure. This body, like the shales and thecomparatively rare paving brick clays, vitrifies very gradually underthe kiln, this characteristic of undergoin ing the essential requirementfor the produc- It is thus evident that the qualities of the materialare primarily due to its chief constituent, sieved coal ashes possessingthe capability of felting, suitably bonded and compressed, and which maybe present in prbportions of to 7 5% by weight of the body.

Specification of Letters Patent.

slow vitrification be- Patented Oct. 26, 1909.

* hpplication filed December 16, 1908. I Serial 1:70. 467,868.

I am aware that it hasbeen proposed to make a fire-brick from a mixtureof hardcoal ashes, shale and fire-clay, but a composition of thischaracter is entirely unsuited for my purposes, Fire-bricks areprimarily intendedto resist high temperatures with repeated heating andcooling without cracking, and are thereforeformed from 'difli cultly.vfusible clays or from mixtures of clay with" inert orinfusible-material's, usually pulverized or ground burnt fire-clay,-termed grog or grit, the Composition remaining porous at the maximumtemperature at which it is to be used. Paving bricks on the other handare required to withstand frost and abrasion. -Porous bricks orfirebricks are useless for this purpose as either of these agencieswould quickly destroy them; Paving bricks must be vitreous in fractureto the point of being'practically' non-absorptive, without beingbrittle. Such vitreous bricks are useless as fire-bricks, even if usedat a temperature lower than that at which they softened or vitrified inthe originalbaking, because on re-heating or in the course of therepeated heatings of the furnace walls, they would crack and spall aftera very short period of use.

I claim:

As a new article of manufacture, a pavin brick or block consistingessentially of sieve coal ashes, possessing the capability of feltingand constituting the refractory portion of the ash, and a bond of claywhich is more fusible than the ash, the proportion of the bond beinginsufliclent to prevent felting of the ashes, said brick beingpractically non-absorptive and having a vitreous fracture.

In testimony whereof, I afiix my signature in presence of two witnesses.

KARL LANGENBEOK.

Witnesses:

HENRY J BOWEN, HARRIETT A. DANN.

